ColdWetDog writes: "Scientists now believe they’ve figured out what causes the uncanny valley response. By using functional MRI and comparing scans of volunteers when watching images of human appearing androids or the humans that the robots were created to mimic, they noted that

"The results suggests that the uneasiness we feel could be caused by a “perceptual mismatch between appearance and motion.” Basically, the brain seemed to negatively react like crazy when the robotic motions of the android didn’t match its human-like appearance.""